The invention relates to gas turbine engine exhaust nozzles, more particularly, an apparatus for exhaust deflection while maintaining a constant exhaust nozzle area of rectangular shape.
A desirable feature of modern aircraft is that the jet efflux may be deflected in a selected direction in order to achieve high maneuverability and vertical or short take-off and landing (V/STOL). The most note-worthy example is that employed by the Harrier's Rolls-Royce Pegasus engine.
The Rolls-Royce Pegasus engine utilizes four swivelling nozzles, two of which are placed toward the front of the aircraft on each side of the fuselage for the passage of by-pass air. The other two are located toward the rear of the aircraft for passing the hot efflux gases from the turbine. By rotating the nozzles from a direction pointing rearward to a position pointed downward, the thrust produced by the nozzles may be selectively directed respectively forward for cruise or upwards for vertical take-off and landing.
Instead of discharging the efflux of hot gases from the engine's turbine through a bifurcated jet pipe, and hence from two vectorable nozzles, it is also known to provide a single jet pipe with a vectorable nozzle to produce forwards or upwards directed thrust.
The invention, as claimed, seeks to provide a vectorable exhaust nozzle for a gas turbine engine in which the flow area is not varied as a direct result of vectoring the nozzle.